Temporal ictal electroencephalographic frequency correlates with hippocampal atrophy and sclerosis

We studied 328 complex partial seizures (CPS) in 63 consecutive patients with temporal lobe epilepsy who underwent scalp electroencephalography/video monitoring, magnetic resonance imaging (MRI), and surgery. The initial ictal discharge (IID), defined as the first sustained electrical seizure pattern localized to the surgical site, was determined. If the IID was rhythmic waves, the median frequency was measured. To determine if IID frequency correlates with hippocampal atrophy (HA) or sclerosis (HS), hippocampal volume ratios (HVRs) were measured (n = 52) or assessed visually (n = 11) on MRI, and mesial temporal histopathology specimens (n = 22) were graded for HS. Sixteen patients (25%) had no or mild HA (HVR = 0.78-1.02), and 47 patients (75%) had moderate-to-marked unilateral (HVR = 0.33?0.76), or bilateral, HA. Theta frequency IIDs were significantly more commonly associated with moderate-to-marked HA than were delta IIDs. Theta frequency IIDs occurred in 19% of patients with mild or no HA, and 79% of patients with moderate-to-marked HA; delta IIDs occurred in 63% of patients with little to no HA, and 13% of those with moderate-to-marked HA. In addition, the median IId frequency inversely correlated with HVR and directly correlated with HS severity. In conclusion, faster frequency rhythmic IIDs during temporal lobe CPS correlate with greater degrees of ipsilateral HA on MRI, and higher grades of HS.     

Clinical ictal patterns in epileptic patients with occipital electroencephalographic foci.

Seizure patterns and other clinical features were analyzed in 55 epileptic patients with electrographic evidence of exclusive or predominant occipital involvement. Few statistically significant differences in clinical or ictal patterns were found between subjects with purely focal occipital involvement and those with temporal and temporo-parietal spread or minor additional independent foci. On the other hand, cases with bilateral synchronous occipital spike activity appeared to reflect a different type of epileptic disorder. Clinical pleomorphism was more apparent than is commonly conceived; thus, although the incidence of visual auras was relatively high (47 percent), epigastric, psychic, somatic, and other sensory phenomena were not infrequently encountered. Ictal motor patterns were most commonly (53 percent) nonfocal or absent, but partial or focal motor attacks and psychomotor seizures were amply represented. Ictal features with their localizing and lateralizing reliability were also analyzed and discussed in relation to those found in a comparison study of seizures of fronto-centro-parietal origin.     

Seizure-related cardiac repolarization abnormalities are associated with ictal hypoxemia

Purpose: Cardiac arrhythmias and respiratory disturbances have been proposed as likely causes for sudden unexpected death in epilepsy. Oxygen desaturation occurs in one‐third of patients with localization‐related epilepsy (LRE) undergoing inpatient video–electroencephalography (EEG) telemetry (VET) as part of their presurgical workup. Ictal‐related oxygen desaturation is accompanied by hypercapnia. Both abnormal lengthening and shortening of the corrected QT interval (QTc) on electrocardiography (ECG) have been reported with seizures. QTc abnormalities are associated with increased risk of sudden cardiac death. We hypothesized that there may be an association between ictal hypoxemia and cardiac repolarization abnormalities. Methods: VET data from patients with refractory LRE were analyzed. Consecutive patients having at least one seizure with accompanying oxygen desaturation below 90% and artifact‐free ECG data were selected. ECG during the 1 min prior to seizure onset (PRE) and during the ictal/postictal period with accompanying oxygen desaturation below 90% (DESAT) was analyzed. Consecutive QT and RR intervals were measured. In the same patients, DESAT seizures were compared with seizures without accompanying oxygen desaturation below 90% (NODESAT). For NODESAT seizures, QT and RR intervals for 2 min after seizure onset were measured. Key Findings: Thirty‐seven DESAT seizures were analyzed in 17 patients with localization‐related epilepsy. A total of 2,448 QT and RR intervals were analyzed during PRE. During DESAT, 1,554 QT and RR intervals were analyzed. Twelve of the 17 patients had at least one NODESAT seizure. A total of 19 NODESAT seizures were analyzed, including 1,558 QT and RR intervals during PRE and 3,408 QT and RR intervals during NODESAT. The odds ratio for an abnormally prolonged (>457 ms) QTcH (Hodges correction method) during DESAT relative to PRE was 10.64 (p < 0.0001). The odds ratio for an abnormally shortened (<372 ms) QTcH during DESAT relative to PRE was 1.65 (p < 0.0001). Seizure‐related shortening and prolongation of QTc during DESAT were also observed when Fridericia correction of the QT was applied. During DESAT seizures, the mean range of QT values (QTr) (61.14 ms) was significantly different from that during PRE (44.43 ms) (p = 0.01). There was a significant association between DESAT QTr and oxygen saturation nadir (p = 0.025) and between DESAT QTr and duration of oxygen desaturation (p < 0.0001). Both QTcH prolongation and shortening also occurred with NODESAT seizures. A seizure‐associated prolonged QTcH was more likely during DESAT than NODESAT, with an odds ratio of 4.30 (p < 0.0001). A seizure‐associated shortened QTcH was more likely during DESAT than NODESAT with an odds ratio of 2.13 (p < 0.0001). Significance: We have shown that the likelihood of abnormal QTcH prolongation is increased 4.3‐fold with seizures that are associated with oxygen desaturation when compared with seizures that are not accompanied with oxygen desaturation. The likelihood of abnormally shortened QTcH increases with seizures that are accompanied by oxygen desaturation with an odds ratio of 2.13 compared with that in seizures without desaturations. There is a significant association between the depth and duration of oxygen desaturation and QTr increase. These findings may be related to the pathophysiology of SUDEP.     

Prolonged ictal paralysis: electroencephalographic confirmation of its epileptic nature

Somato-inhibitory status epilepticus is a rare condition which may pose some problems of differential diagnosis. The authors describe the case of a girl who suffered from episodes of prolonged ictal paralysis lasting from some minutes to some hours. One seizure was described 2 hours from onset. The EEG showed a continuous spike activity on the right side, predominantly on the parieto-rolandic areas. Status was stopped by the administration of clobazam per os. The physiopathological mechanism of this rare form of status epilepticus is discussed.     

Paradoxical lateralization of non-invasive electroencephalographic ictal patterns in extra-temporal epilepsies

Video-electroencephalographic (EEG) ictal recordings play an important role in the pre-surgical evaluation of patients with medically refractory focal epilepsy. Paradoxical lateralization of the scalp EEG ictal onset patterns, consistently contralateral to the side of the proven epileptogenic lesion is rare but important to recognize, with possible implications on patient management. We searched the database of the University of Munich Epilepsy Monitoring Unit for patients with extratemporal epilepsies, with scalp EEG ictal patterns consistently contralateral to the proven epileptogenic zone. All available clinical, EEG and imaging data were reviewed. Dipole source analysis of EEG seizure onset was performed where possible. Four patients were identified, who had proven paradoxical lateralization of scalp EEG ictal patterns, demonstrated by seizure freedom after epilepsy surgery, data from invasive electroencephalography, or imaging and seizure semiology. Parasagittal lesions on MRI brain scan were found in three cases. Invasive recordings with subdural electrodes were performed in one patient. Dipole source analysis of EEG seizure onset was possible in two patients, helping to correctly lateralize the ictal EEG pattern in one patient. Patients with midline or near midline neocortical seizure foci may show paradoxical lateralization of the ictal EEG, likely due to the spatial orientation of the cortical generators in the medial regions of the cerebral hemispheres. These patients may have excellent surgical outcome despite the apparently discordant EEG findings, making this an important phenomenon to be recognized in clinical practice.     

Topographic electroencephalographic study of transient ischemic attacks

Twenty-five patients with TIAs in the carotid artery distribution were studied by means of computed mapping of EEG (CME) and conventional EEG. In addition, CT scan and cerebral angiography, and in 10 patients rCBF measurements were performed. The CME provided topographic maps of the average power spectra for each of 6 frequency bands from 2.0 to 29.5 Hz which were displayed two-dimensionally in a color-coded isopower format. EEG abnormalities were analyzed and the results of the two different methods of EEG interpretation were compared. Sixty-eight percent of the patients showed unilateral abnormalities on CME appropriately lateralized to the clinical symptoms even after these symptoms had cleared completely. Furthermore, 88% of those who were examined within 2 weeks of last TIA showed corresponding CME abnormalities. Only 3 out of 10 TIA patients who had rCBF studies showed reduction of blood flow on the appropriate hemisphere, whereas 7 of the 10 patients had corresponding CME abnormalities. Comparing the results of the CME and of conventional EEG reading revealed the CME to be slightly more sensitive in detecting asymmetrical voltage depression of background activity than the conventional reading of the EEG, while the latter detected low amplitude sporadic activities which were missed by CME. Both methods were equally sensitive in detecting slow wave foci and non-transient symmetrical changes. The two most significant points of this report are the following: first, 68% of the TIA patients studied had residual unilateral abnormalities in CME in their symptom-free period. In the subset of patients subjected to rCBF studies only 30% showed residual flow aberrations, whereas 70% of the same subset demonstrated unilateral abnormalities in CME. Second, though conventional EEG reading by an experienced electroencephalographer can nearly match the performance of CME the CME format makes subtle but useful EEG findings readily available to the uninitiated. The CME also quantifies the data making objective comparisons more amenable to software manipulations for further studies.     

Correlation between scalp-recorded electroencephalographic and electrocorticographic activities during ictal period.

OBJECTIVE: To investigate the correlation between scalp-recorded electroencephalographic (EEG) and electrocorticographic (ECoG) activities during ictal periods. METHODS: Simultaneous EEG and ECoG recordings with chronic subdural electrodes were performed in eight patients with partial epilepsy. RESULTS: In two cases where the ictal ECoG discharges originated in deep brain structures such as the hippocampus and interhemispheric surface of the frontal lobe, ictal discharges could not be detected on EEG until they expanded to the cortex of convexity. In four cases, the ictal onset zones were located in the lateral convexity. When synchronous or near synchronous ictal ECoG discharges with amplitudes of 200-2000muV were recorded on more than 8-15cm(2) of cortex, corresponding discharges were recorded on EEG in these four cases. However, in a case of frontal lobe epilepsy, asynchronous ictal ECoG discharges were recorded on 10 electrodes of convexity but no ictal EEG activity was recorded. Furthermore, in two frontal lobe epilepsy cases, ictal EEG discharges did not always reflect the ictal ECoG spike, but occasionally reflected slow background ECoG activity around the ictal discharges. CONCLUSIONS: Multiple factors such as the width of the cortical area involved, amplitude of ictal discharges and degree of synchronization of electrical potentials play important roles in the appearance of ictal EEG recordings, and the relationship between ictal EEG and ECoG is not straightforward.     

Anticonvulsant-responsive panic attacks with temporal lobe EEG abnormalities

The phenomenology of panic attacks and of complex partial seizures overlap, and at times distinguishing between the two entities is difficult. The authors report five patients with recurrent panic attacks and temporal lobe EEG abnormalities whose symptoms did not warrant a clinical diagnosis of partial seizures but who responded well to anticonvulsant therapy. The cases suggest that focal cortical discharges may trigger panic attacks in some patients in whom an unequivocal diagnosis of epilepsy cannot be made. Electroencephalography and anticonvulsant trials may be appropriate in patients with panic attacks refractory to conventional treatment.     

Epileptiform electroencephalographic abnormalities in liver transplant recipients

We retrospectively studied patients who had undergone orthotopic liver transplantation and who also had electroencephalography to determine whether epileptiform changes were associated with a poor neurological outcome. Study groups were 36 patients who died after transplantation (141 electroencephalograms) and underwent neuropathological examination, 11 who died (18 electroencephalograms) but did not have autopsy, and a third group of 34 (62 electroencephalograms) who remained alive. Epileptiform activity was seen in electroencephalograms of 14 of the patients who died (11 from the autopsy group) and in 2 of those who remained alive. All had multiple epileptiform abnormalities and clinical or subclinical seizures. The incidence of epileptiform activity after orthotopic liver transplantation was fivefold higher in the nonsurvivors. Serious cerebral structural changes were found in 10 of the 11 patients who underwent autopsy. Epileptiform activity in the electroencephalograms of patients who had undergone orthotopic liver transplantation indicates a poor prognosis. It should alert the clinician to investigate further for potentially treatable causes.     

Cranial computed tomographic and electroencephalographic abnormalities in children with post-hemiconvulsive hemiplegia

Twenty-five children with post-hemiconvulsive hemiplegia, who had had epileptiform discharges on EEG, were followed for over 5 years. Twenty-two of them developed the hemiconvulsion-hemiplegia-epilepsy syndrome. The computed tomographic (CT) findings were: marked hemispheric atrophy in 13 cases; moderate or slight hemispheric atrophy in 4; focal atrophy or porencephaly in 4, and a normal scan in 4. The electroencephalographic (EEG) findings showed residual asymmetry of hemispheric amplitudes in 15 cases. Epileptiform discharges on EEG were found on the ipsilateral side (the damaged hemisphere) in 13 cases, the contralateral side (the undamaged hemisphere) in 9, and on both sides in 3. As to the correlation between CT and EEG abnormalities, 8 of 13 cases with marked hemiatrophy on CT had contralateral epileptiform discharges on EEG, and the converse was more pronounced: 8 of 9 cases with contralateral epileptiform discharges had marked hemiatrophy on CT. Contralateral epileptiform EEG abnormalities were observed in the patient with severe hemispheric brain damage.     

发作性运动诱发性舞蹈指痉症

目的 对发作性运动诱发性舞蹈指痉症的临床特点、电生理表现及发病机制等进行分析。方法 对2001-2003年收治的4例发作性运动诱发性舞蹈指痉症患的临床资料进行分析并复习近年献。结果 4例患均为青年，无家族遗传史，临床表现均为在运动开始时突然出现一侧或双侧肢体及面部的不自主运动，持续数秒钟后可自行缓解，发作期间无意识障碍，发作后无任何不适。4例患神经系统检查、脑电图以及头部CT和(或)MRI检查均无异常发现，诊断为特发性发作性运动诱发性舞蹈指痉症。经服用卡马西平等药物后发作均得到有效控制。结论 发作性运动诱发性舞蹈指痉症可呈常染色体显性遗传，亦可散发；可为特发性，也可继发于多发性硬化、特发性甲状旁腺功能减退症等其他疾病。发作性运动诱发性舞蹈指痉症的发病机制尚不清楚，其临床特征为运动诱发的一侧或双侧上下肢及面部的不自主运动，对抗癫痫药物敏感，预后良好。     

Epilepsy, electroencephalographic abnormalities, and regression in children with autism

The association of epilepsy and autism is recognized, and it has been reported at a percentage that varies between 8 and 42%, depending on age and diagnostic criteria. One third of autistic children undergo a regression of language and behavior between 2 and 3 years, and epileptiform abnormalities and epilepsy can be concomitant in an undetermined percentage of them. The aim of this study was to investigate the prevalence of epilepsy and paroxysmal abnormalities in a group of children with autism and to determine the percentage of regression course in this group. Forty-six patients with autism (mean age 7.8 +/- 2.7 years; 34 boys and 12 girls) were consecutively examined, and clinical evaluation, assessment, and electroencephalographic (EEG) recordings were performed in all of them. Thirty-five percent showed paroxysmal abnormalities and epilepsy, 22% had only paroxysmal abnormalities without seizures, and 13% of the children suffered from epilepsy. Sixty-five percent had a normal EEG. No difference in regression rate was observed between patients with paroxysmal abnormalities and epilepsy and those with a normal EEG and without seizures. In the study group, the prevalence of epilepsy was in the low range of individuals with autism, and different types of epilepsy were observed. Autism with regression was not influenced by paroxysmal abnormalities and epilepsy.     

Temporal evolution of electroencephalographic abnormalities in Creutzfeldt-Jakob disease

Summary Frequent serial EEG investigations of three patients with neuropathologically confirmed Creutzfeldt-Jakob disease lasting 13, 24 and 68 weeks revealed typical periodic activity of short duration with stereotyped bilateral sharp waves at the 7th, 8th, and 12th week, respectively, after the onset of symptoms. During the later stages, there were several deviations from this typical pattern. However, periodic activity was preceded between the 3rd and 9th week by intermittent localized or lateralized delta rhythms, which gradually changed into periodic activity. This early temporal evolution of EEG abnormalities may be helpful in the early diagnosis of Creutzfeldt-Jakob disease when accompanied by other investigations to exclude other causes of intermittent delta rhythms.     

Nonketotic hyperglycinemia: electroencephalographic and evoked potential abnormalities

Five patients with nonketotic hyperglycinemia had serial EEGs and evoked-response studies. EEGs were grossly abnormal in all patients. In the neonatal period, the "suppression-burst" pattern was observed. The EEG changed to hypsarrhythmia during early or mid-infancy. In the second to fifth years of life, multifocal epileptiform discharges superimposed on diffuse slow background activity constituted the usual abnormality during wakefulness, but more severe disorganization of the EEG occurred in sleep with emergence of hypsarrhythmia. Four patients had abnormal brainstem auditory evoked responses, characterized by prolongation of I-V interval, and two had abnormal flash-induced visual evoked responses.     

Focal electroencephalographic abnormalities and computerised tomography findings in children with seizures.

A persistent focal abnormality was observed in 157 (16%) electroencephalograms undertaken in 964 consecutive children with epileptic and non-epileptic seizures seen over one year. CT head scans were performed in 121 (77%) of the 157 children with a focus on the EEG; 26 (21%) showed an abnormality, and 21 (81%) of the abnormalities were localised. There was no difference in the proportion of abnormal scans associated with a delta or slow wave focus compared with a spike or sharp wave focus. An abnormal scan was uncommon after a single seizure. In only two patients (1.7% of all scans) did the findings on CT alter or greatly influence subsequent management.     

Epileptiform abnormalities discovered on electroencephalographic screening of psychiatric inpatients

The results of electroencephalographic screening of 3225 inpatients from a community general hospital psychiatric service were reviewed. When patients with a prior diagnosis of epilepsy were excluded, epileptiform abnormalities were discovered in 2.6% of patients. Patients younger than age 25 years and patients with a diagnostic impression of anorexia nervosa, recent barbiturate abuse, or nonpsychotic explosive behavior were significantly more likely to have epileptiform abnormalities. The use of certain therapeutic agents was associated with a significant excess of epileptiform abnormalities in patients aged 25 years and older. The most frequently encountered epileptiform abnormalities were photoconvulsive responses. Focal temporal epileptiform abnormalities were detected in only four patients without a prior diagnosis of epilepsy. The diagnosis of epilepsy on the basis of a primarily psychiatric presentation and the discovery of epileptiform abnormalities on electroencephalographic screening should be approached with caution.